COMPARISON STUDY OF ADAPTIVE CONTROLLERS FOR ROBOT MANIPULATORS

The performance of two adaptive robot control algorithms, namely the a daptive algorithm by Slotine and Li and the proposed direct adaptive f uzzy control algorithm, were studied. In Slotine and Li's method, the algorithm consists of proportional derivative feedback and a full dyna mics feedforward part, with the unknown manipulator and payload parame ters being estimated on-line. The algorithm depends heavily on the par ticular structure of manipulator dynamics and needed three simplifying properties to derive the adaptive law. The direct adaptive fuzzy algo rithm uses a fuzzy logic system as the controller. The derivation of t he controller does not require any knowledge of the manipulator dynami cs and the uncertainty in the system, only the boundary of the dynamic s. The predominant concern of the two adaptation laws is to reduce the tracking errors. In particular, they require no feedback of joint acc elerations. Theoretical results and simulation studies on a two-link r obot manipulator show that both methods are robust and stable. The dir ect adaptive fuzzy controller outperforms the adaptive controller in m ass variation. (C) 1996 John Wiley and Sons, Inc.